1. Field of the Invention
The present invention relates generally to improved athletic equipment, wherein the qualities of high strength, light weight and superior stiffness are required. This invention also provides a method for making such equipment. The outstanding characteristics and benefits achieved are described with reference to javelins as an example.
2. Description of the Prior Art
Throwing the javelin is one of a number of track and field events whose origins go back to the days of ancient Greece and perhaps even further. Originally derived from spears or similar military devices, the javelin has not evolved much over the years. Part of this problem has arisen because its current structure and shape are more or less controlled by the requirements of current International Olympic Committee (IOC) Rule 185-14 as follows:
"The javelin shall consist of three parts: a metal head, a shaft, and a cord grip. The shaft may be constructed of either wood or metal and it shall have fixed to it a metal head terminating a sharp point. PA0 "The cord shall be about the centre of gravity without thongs, notches or identations of any kind on the shaft, and shall not exceed the circumference of the shaft by more than 25 millimeters (1 in.). The binding shall be of uniform thickness. PA0 "The cross-section shall be regularly circular throughout and the maximum diameter thereof shall be under the grip. From the grip the javelin shall taper gradually to the tip of the metal head and the rear tip. The line from the end of the grip to the tip of the metal head may be straight or slightly curved, but the curve must be gradual and there must be no abrupt alteration in the diameter of the section throughout the length of the javelin. PA0 "Note: Wilst the cross section should be circular, a maximum difference between the biggest and the smallest diameter of the oval of 5 percent is permitted. The mean value of these 2 diameters must correspond to the specification given for a circular javelin. PA0 "It shall conform to the following specifications: PA0 "The javelin shall have no mobile parts or other apparatus which during the throw could change its centre of gravity or throwing characteristics. PA0 "The tapering of the shaft from the maximum diameter to the tip of the metal head or to the rear tip shall be such that the diameter at the midpoint between the end of the cord grip and either tip shall not exceed 90 percent of the maximum diameter of the shaft and that at a point 150 millimeters from either tip 80 percent of the maximum diameter."
CHART ______________________________________ Javelin Men Women ______________________________________ Weight Min. 800 g 600 g inclusive of cord grip Overall Min. 2.60 m 2.20 m length Max. 2.70 m 2.30 m Length of Min. 250 mm 250 mm metal head Max. 330 mm 330 mm Distance from Min. 0.90 m 0.80 m tip of metal Max. 1.10 m 0.95 m heat to centre of gravity Diameter of Min. 25 mm 20 mm shaft at Max. 30 mm 25 mm thickest point Width of Min. 150 mm 140 mm cord grip Max. 160 mm 150 mm ______________________________________
Over the last thirty years or so, as a result of the development of polymer, glass, boron and, most recently, carbon/graphite based composites there have been considerable improvements in the design and construction of many types of athletic equipment. These have included vaulting poles, golf clubs, tennis rackets (U.S. Pat. Nos. 4,070,020 to Dano, 4,023,799 to Van Auken, 3,981,504 to Gugel, 3,889,951 to Schaefer, et al. and 3,787,051 to Johns), fishing rods (U.S Pat. Nos. 4,043,074 to Airhart, 4,015,360 to Herter and 3,953,637 to Phillips) and skis (U.S. Pat. No. 3,902,732 to Fosha, et al.). However, one finds that there has been essentially no application of this technology to the design and development of improved javelins. Rather, the effort has primarily been directed to making minor improvements within the constraints of the IOC Rules. Thus, one finds most work on javelins being expended either to make an improved wooden item (U.S. Pat. Nos. 2,196,610 to Schlademan, et al., 1,731,686 to Rinneberg and 1,552,442 to Lund), to provide a stronger head/point construction (U.S. Pat. Nos. 2,122,023 to Campbell, et al., 2,044,092 to Manzeck, 1,994,089 to Pipal and 1,569,395 to Reach) which is less likely to break on impact, or to make a lighter weight metallic javelin. These efforts have succeeded to the point where modern javelins are indeed better than their predecessors of even 20 years ago. However, it is also known that the modern javelin, based as it is on a Grecian spear, is still far from optimum in regard to its flight properties. This, when combined with the relatively high densities of the currently allowed materials of construction, results in a considerable reduction in the maximum throwing distance a well trained athlete should expect to achieve with a properly designed javelin. The subject invention is intended to correct this situation and to provide a composite javelin having considerably improved physical and flight properties as compared to current wooden or metal models.